蜂鸣器与继电器的基本控制

#include"reg52.h"
int i;
void SelectHC573(unsigned char n){
	switch(n){
		case 4:
			P2 = (P2 & 0x1f) | 0x80;
		break;
		case 5:
			P2 = (P2 & 0x1f) | 0xa0;
		break;
		case 6:
			P2 = (P2 & 0x1f) | 0xc0;
		break;
		case 7:
			P2 = (P2 & 0x1f) | 0xe0;
		break;
	}
}
void delay(unsigned char t){
	for(i=0;i<3000;i++){
	while(t--);
	while(t--);
	}


}
void led(){
	SelectHC573(4);
	P0=0x00;
	delay(9000);
	P0=0xff;
	delay(9000);
	

}
void fengming(){
	SelectHC573(5);
	P0 = 0x40;
	delay(900);
	delay(900);
	P0 = 0x00;
}
void jidian(){
	SelectHC573(5);
	P0 = 0x10;
	delay(90000);
	delay(90000);
	P0 = 0x00;
} 



void main(){ 
	SelectHC573(4);
	P0=0xff;

	while(1){
	fengming();
	led();
	jidian();
	}

}